Goals: Ranger 3 was NASA's first attempt to make a hard landing on the Moon. The spacecraft was designed to deploy a small instrument package containing a seismometer on the lunar surface.

Accomplishments: A malfunction in the spacecraft's guidance system sent Ranger 3 hurtling past the Moon at a distance of 36,793 km (22,862 miles). It was traveling too fast to enter lunar orbit. The spacecraft did provide the first measurements of interplanetary gamma-ray flux. Ranger 3 eventually settled into a heliocentric (sun-centered) orbit.